JP4637440B2 - Manufacturing method of ceramic element - Google Patents

Description

【００３１】
樹脂層７を設けない場合における保護膜欠陥発生率を保護膜６の厚みを変えて測定したところ、次の表２に示す結果が得られた。
【００３２】

【００３３】
保護膜６と樹脂層７との両方を有する積層バリスタを回路基板に半田リフロ−で固着した時の第１及び第２の外部電極４、５間のＩＲ(絶縁抵抗)の変化率（％）を保護膜6の厚みを変えて測定したところ、次の表3の結果が得られた。なお、ＩＲの変化率とはリフロ−前のＩＲとリフロ−後のＩＲとの割合を示す。
【００３４】

【００３５】
樹脂層7を設けないで保護膜6のみを設けた積層バリスタを回路基板に半田リフロ−で固着した時の第1及び第2の外部電極４、５間のＩＲの変化率（％）を保護膜6の厚みを変えて測定したところ、次の表4の結果が得られた。
【００３６】

【００３７】
保護膜６と樹脂層７とを有する積層バリスタの回路基板に対する半田リフロ−による接続のコンタクト不良率（％）を保護膜6の厚みを変えて測定したところ、次の表５の結果が得られた。
【００３８】

【００３９】
樹脂層7を設けないで保護膜6のみを設けた積層バリスタの回路基板に半田リフロ−による接続のコンタクト不良率（％）を保護膜6の厚みを変えて測定したところ、次の表６の結果が得られた。
【００４０】

【００４１】
上記表1〜表６から、保護膜6の厚みは０．０５〜２μｍであることが好ましく、０．１〜１μｍがより好ましいことが判る。なお、上記表1〜表６には、保護膜6をＲＦスパッタで形成した場合が示されているが、保護膜6をＣＶＤで形成した場合も表1〜表6と同様な結果が得られた。
【００４２】
本実施形態は次の効果を有する。
（１） ＡｌｘＯｙから成る保護膜６が、セラミック素体１の外部電極４、５が形成されていない部分のみでなく、外部電極４、５の下にも設けられている。
従って、外部電極４、５の形成部分と形成されていない部分との境界における保護が良好に達成される。即ち、第１及び第２のメッキ層１６、１７、１８、１９を形成する時の処理液のセラミック素体１への浸入、及びバリスタの回路基板への実装時における半田フラックスのセラミック素体１への侵入を良好に防ぎ、セラミック素体１のＩＲ特性等の劣化を防ぐことができる。
（２） 内部電極２、３と外部電極４、５との電気的接続が、Ａｇ導体層１４、１５の焼付時の内部電極２、３の突き出しによって達成されているので、この電気的接続を容易に達成することができる。
（３） ＡｌｘＯｙの保護膜６の上にシリコ−ン樹脂層７を形成し、保護膜６の空隙に樹脂を充填しているので、保護機能を大幅に向上させることができる。
（４） 保護膜６をＲＦスパッタ法又はＣＶＤ法で作るので、目的とする保護膜６を比較的容易に作ることができる。
【００４３】
【変形例】
本発明は、上述の実施形態に限定されるものでなく、例えば次の変形が可能なものである。
（１） 内部電極２、３の材料は、Ｐｄと同様な作用を得ることができるものであれば別のものでもよい。また、内部電極２、３はＰｄを主成分とし、別の金属を副成分として含むものでもよい。
（２） 保護膜６は、本発明の要求を満たすことができるものであれば、ＡｌｘＯｙ以外の物質でもよい。
（３） 外部電極４、５の導体層１４、１５はＡｇ以外の例えばＡｇ−Ｐｄペ−スト等であってもよい。
（４） ＡｌｘＯｙ保護膜６とシリコ−ン樹脂層７との複合構成は、外部電極４、５の下に保護膜６を設けない構成のセラミック素子の保護層としても適用できる。
（５） ＺｎＯバリスタ以外のセラミック積層コンデンサ、セラミック積層サ−ミスタ等のセラミック素子にも本発明を適用できる。
（６） 樹脂層７をシリコ−ン以外の同様な機能を有する高分子樹脂とすることができる。
【図面の簡単な説明】
【図１】本発明の実施形態に従うＺｎＯ積層バリスタを示す平面図である。
【図２】図１のＡ−Ａ線断面図である。
【図３】セラミック素体に保護膜を形成したものを示す断面図である。
【図４】Ａｇ導体層を形成したものを示す断面図である。
【図５】シリコ−ン樹脂層７を形成したものを示す断面図である。
【図６】図５の保護膜６とシリコ−ン樹脂層７との一部を説明的に拡大して示す図である。
【符号の説明】
１ セラミック素体
２、３ 内部電極
４、５ 外部電極
６ 保護膜
７ シリコ−ン樹脂層
８、９ 主面
１０、１１、１２、 １３ 側面
１４、１５ Ａｇ導体層
１６、１７ 第１のメッキ層
１８、１９ 第２のメッキ層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manufacturing method of a ceramic element such as ZnO multilayer varistor.
[0002]
[Prior art]
The ZnO multilayer varistor includes an element body mainly composed of ZnO, one internal electrode embedded in the element body and led out to one side surface of the element body, and embedded in the element body and formed on the other side surface of the element body. The other internal electrode is formed, one external electrode disposed on one side surface of the element body, and the other external electrode disposed on the other side surface of the element body. The external electrode includes a conductive layer formed by applying and baking a conductive paste and a metal layer formed by plating on the conductive layer in order to improve solderability.
[0003]
[Problems to be solved by the invention]
By the way, since the ZnO particles of the ZnO laminated varistor are made into semiconductors, they are easily dissolved in acid and easily cause oxygen defects. For this reason, the insulation resistance of the varistor, that is, the deterioration of the IR occurs due to the reducing action of the solder flux when forming the plating layer of the external electrode and mounting the varistor element on the circuit board.
This kind of deterioration can be prevented to some extent by forming a protective film having acid resistance, insulation and denseness on the exposed surface of the ceramic body. However, in the conventional ceramic element, since the protective film is formed only on the exposed surface of the ceramic body, the plating solution and the solder flux may enter from the boundary between the protective film and the external electrode, which may cause deterioration. there were.
As mentioned above, the conventional ZnO multilayer varistor has been described, but there is a similar problem also in other ceramic elements such as a ceramic multilayer capacitor and a ceramic multilayer thermistor.
There is also a problem that a good quality protective film cannot be easily formed.
[0004]
An object of the present invention is to provide a method for producing a ceramic element which can be satisfactorily achieved to prevent deterioration. Another object of the present invention is to provide a method for producing a ceramic element which can be easily formed a high-quality protective film.
[0005]
[Means for Solving the Problems]
In order to solve the above problems and achieve the above object, the present invention provides:
An internal electrode formed of Pd or Pd-Ag embedded in the ceramic body and having a property of volume expansion by heating so as to have a ceramic body and an end face exposed at a part of the outer peripheral surface of the ceramic body Preparing a ceramic element chip comprising:
A protective film made of an oxide of aluminum that covers the entire outer peripheral surface of the ceramic body and has a thickness of 0.05 to 2 μm and that can be expressed by AlxOy, where x and y are arbitrary numerical values. And a process of
Applying an external electrode paste so as to cover a part of the outer peripheral surface of the ceramic body through the protective film;
The external electrode pair - to form a result external electrode baking at a temperature in the range of strike the 500 to 800 ° C. the internal electrodes at the same time by volume expansion defeating portion of the protective film by the internal electrode, the internal And a step of electrically connecting the electrode and the external electrode. The present invention relates to a method for manufacturing a ceramic element.
[0006]
According to a second aspect of the present invention, it is desirable to further include a step of forming a metal layer on the surface of the external electrode by a plating method.
According to a third aspect of the present invention, there is further provided a step of forming a silicone resin layer so as to cover a portion of the protective film that is not covered with the external electrode, and a metal is formed on the surface of the external electrode by plating. And a step of forming a layer.
Moreover, it is desirable to form the protective film by a high frequency sputtering method.
Further, as shown in claim 5, it is preferable to form the protective film by chemical vapor layer deposition.
[0007]
The ceramic body according to the present invention includes various known ceramic bodies for varistors, ceramic bodies for capacitors, ceramic bodies for thermistors, and the like.
The internal electrode according to the present invention is preferably a Pd or palladium electrode, but other electrode materials such as a Pd-Ag electrode may also be used.
The protective film according to the present invention is preferably an oxide of aluminum that can be represented by AlxOy, provided that it has a protective function and can protrude the internal electrode and remains under the external electrode, Another material may be used.
The external electrode according to the present invention is formed of a material that does not absorb the protective film by reacting with the protective film.
The resin layer according to the present invention is preferably a silicone resin layer, but may be a polymer resin having a similar function.
[0008]
【The invention's effect】
According to the first to fifth aspects of the present invention, the following effects can be obtained.
(1) The entire outer peripheral surface of the ceramic body has a thickness of 0.05 to 2 μm except for the portion broken by the protrusion of the internal electrode, and AlxOy, where x and y are arbitrary numerical values. The protective film is made of an oxide of aluminum, and the protective film is also interposed between the external electrode and the ceramic body. For this reason, it is possible to satisfactorily prevent the intrusion of the plating solution, the solder flux and the like at the boundary between the external electrode and the ceramic body, which may occur in the conventional ceramic element.
(2) Since the protective film made of AlxOy having a thickness of 0.05 to 2 μm is broken by the protrusion of the internal electrode made of Pd or Pd-Ag , the protective film interferes with the electrical connection between the internal electrode and the external electrode. Without this, electrical connection between the internal electrode and the external electrode is easily achieved .
According to the third aspect of the present invention, it is possible to satisfactorily prevent intrusion of a substance that causes deterioration by a combination of a protective film made of AlxOy and a silicone resin.
[0009]
Embodiment
Next, a ZnO multilayer varistor as a ceramic element according to the embodiment will be described with reference to FIGS.
[0010]
As shown in FIG. 1 and FIG. 2, this varistor can obtain varistor characteristics, a porcelain element body, that is, a ceramic element body 1, first and second inner electrodes 2, 3, and first and second elements. The external electrodes 4 and 5, the protective film 6, and the silicon resin layer 7 are formed.
[0011]
The ceramic body 1 is made of, for example, a grease formed by adding subcomponents such as Pr ₆ O ₁₁ , CoO, CaCO ₃ , SrCO ₃ , SiO ₂ , and Al ₂ O ₃ to a main component composed of, for example, ZnO. -A sheet made of laminated and fired unsintered ceramic sheets and has varistor characteristics. The ceramic body 1 is a hexahedron or long body having first and second main surfaces 8 and 9 facing each other and first, second, third and fourth side surfaces 10, 11, 12, and 13. It is a cuboid.
[0012]
The two first internal electrodes 2 and the two second internal electrodes 3 are embedded in the ceramic body 1 so as to face each other through a part of the ceramic body 1. The first internal electrode 2 has an end surface exposed from the first side surface 10 of the ceramic body 1. The second internal electrode 3 has an end surface exposed from the second side surface 11 of the ceramic body 1. The first and second inner electrodes 2 and 3 are made of Pd, that is, palladium.
[0013]
The first and second external electrodes 4, 5 cover the first and second side surfaces 8, 9 of the ceramic body 1 facing each other through the protective film 6, and the first and second main surfaces 8, 9. And part of the third and fourth side faces 12 and 13 are also formed. The first and second inner electrodes 2, 3 break a part of the protective film 6 and protrude outward, and are electrically connected to the first and second outer electrodes 4, 5. The first and second external electrodes 4, 5 are composed of baked conductor layers 14, 15, first plating layers 16, 17, and second plating layers 18, 19. The baked conductor layers 14 and 15 are made by applying and baking Ag paste. The first plating layers 16 and 17 are Ni (nickel) layers, and the second plating layers 18 and 19 are Sn (tin) layers.
[0014]
The protective film 6 protects the ceramic body 1 from the plating solution and the solder flux. The entire outer peripheral surface of the ceramic body 1, that is, the first and second main surfaces 8 and 9 and the first to fourth side surfaces. 10 to 13 are formed. The protective film 6 is made of an oxide of aluminum which can be expressed by AlxOy, where x and y are arbitrary numerical values. AlxOy of the protective film 6 can be formed by RF (high frequency) sputtering using Al ₂ O ₃ as a target, or CVD, that is, chemical vapor deposition, where x is 2 or less than 2, y has a value of 3 or less than 3.
The protective film 6 according to the present invention has relatively good insulating properties, acid resistance and denseness, and does not easily melt with respect to the external electrodes 4 and 5. Further, the protective film 6 has a thickness that can be broken by the protrusion due to the expansion of the first and second internal electrodes 2, 3 when forming the baked conductor layers 14, 15, preferably 0.05-2 μm, more preferably 0.1 to 1.0 μm.
[0015]
The silicon resin layer 7 is disposed so as to cover a portion of the protective film 6 that is not covered with the external electrodes 4 and 5, and is not only on the surface of the protective film 6 as illustrated in an enlarged manner in FIG. The inside of the protective film 6 and the defective part 20 of the protective film 6 are also filled. The composite layer portion of the protective film 6 made of AlxOy and the silicone resin layer 7 is superior to the case of only the AlxOy film in acid resistance, insulation and denseness.
[0016]
[First manufacturing method]
When producing the laminated varistor mainly composed of ZnO shown in FIGS. 1 and 2, first, a green sheet mainly composed of ZnO is prepared. Namely, ZnO as a main component and Pr ₆ O ₁₁ , CoO, CaCO ₃ , SrCO ₃ , SiO ₂ , and Al ₂ O ₃ as desired components added in a desired amount are mixed in a wet ball mill for 16 hours. And dried to obtain a ceramic raw material powder.
[0017]
Next, a slurry was prepared by mixing an organic binder, an organic solvent, and an organic plasticizer with the ceramic raw material powder for 20 hours using a ball mill.
[0018]
Next, using the above slurry, a green sheet having a thickness of 30 μm was prepared on a PET film by a known sheet preparation doctor blade method and cut into a predetermined size.
[0019]
In order to form the internal electrodes 2 and 3, a Pd paste comprising Pd powder, a solvent and an organic binder is prepared, and the Pd paste is printed on a predetermined pattern on the cut green sheet. A green sheet printed with Pd paste and a green sheet not printed so as to obtain a laminate of the ceramic body 1 and the internal electrodes 2 and 3 shown in FIGS. After laminating and thermocompression bonding, the chip was cut into a predetermined shape to produce a green chip.
[0020]
Next, the green chip is subjected to a binder removal treatment at 300 ° C. for 2 hours, and then fired in air, that is, in an oxidizing atmosphere at 1200 ° C. for 2 hours, to form a ceramic body 1 composed of sintered ceramics. Got. The internal electrodes 2 and 3 are exposed on the first and second side faces 10 and 11 of the ceramic body 1 as shown in FIG.
[0021]
Next, the surface of the ceramic body 1 including the internal electrodes 2 and 3 is smoothed by a known barrel polishing method.
[0022]
Next, the ceramic body 1 is put into a well-known drum rotating RF sputtering apparatus, and sputtering is performed using Al ₂ O ₃ as a target. As shown in FIG. 3, aluminum is oxidized on the entire outer peripheral surface of the ceramic body 1. A protective film 6 made of a material is formed. The protective film 6 is made of an aluminum compound represented by AlxOy, where x and y are arbitrary numerical values. Note that x and y are preferably arbitrary numerical values selected from x ≦ 2 and y ≦ 3. The protective film 6 has acid resistance, insulation, and denseness to protect the ceramic body 1 and allows the internal electrodes 2 and 3 to protrude. In order to satisfy the above conditions, the thickness of the protective film 6 is preferably in the range of 0, 05 to 2 μm, more preferably in the range of 0.1 to 1.0 μm. Since the ceramic body 1 is barrel-polished before the sputtering step to obtain a surface with less unevenness, the protective film 6 is satisfactorily formed on the ceramic body 1.
[0023]
Next, in order to form the baked conductor layers 14 and 15 of the external electrodes 4 and 5, a well-known Ag paste comprising Ag (silver) powder, a solvent, an organic binder, and glass frit is prepared. The first and second side surfaces 10 and 11 of the ceramic body 1 and the first and second main surfaces 8 and 9 and the third and fourth side surfaces 12 and 13 through the protective film 6 4 and is baked in air at a temperature of 720 ° C. selected preferably from 500 to 800 ° C. for about 8 minutes to obtain the baked conductor layers 14 and 15 shown in FIG. By the way, Pd constituting the internal electrodes 2 and 3 has the property of being oxidized by heating and then reduced. For this reason, when the baking process of Ag paste is performed in air or in an oxidizing atmosphere, volume expansion of internal voltages 2 and 3 occurs due to oxidation of Pd, and the internal electrodes 2 and 3 are connected to the first and second side surfaces. 10 and 11, the protective film 6 is broken, contacts the Ag conductor layers 14 and 15, forms an alloying layer, and electrical connection between the internal electrodes 2 and 3 and the Ag conductor layers 14 and 15 is established. In this baking process, the protective film 6 made of AlxOy remains in the conductor layers 14 and 15 without melting. It is confirmed by EPMA analysis, that is, electron probe microanalysis, that the protective film 6 remains between the Ag conductor layers 14 and 15 and the ceramic body 1.
[0024]
Next, in order to improve the denseness of the protective film 6, the ceramic body 1 having the protective film 6 is placed in a solution obtained by diluting a resin, for example, a silicone resin with a solvent such as toluene. If the protective film 6 has a defective portion 19 as shown in FIG. 6, it is filled with resin, and then air-dried and heat-cured to perform a silicone resin layer. 7 is formed.
[0025]
Next, the silicon resin layer formed on the external electrode conductor layers 14 and 15 is removed. This step can be omitted when the resin layer is not formed on the external electrode layers 14 and 15.
[0026]
Next, first plating layers 16 and 17 made of Ni and second plating layers 18 and 19 made of Sn are sequentially formed by a well-known barrel plating method to complete the ceramic element of FIG.
[0027]
[Second manufacturing method]
In the first manufacturing method described above, the protective film 6 is formed by RF sputtering, but can be formed by CVD, that is, chemical vapor deposition. When the protective film 6 is formed by CVD, the ceramic body 1 with the internal electrodes 2 and 3 is arranged on a plate of a known CVD film forming apparatus, and preferably 400 to 600 ° C., more preferably 500 ° C. A protective film 6 made of AlxOy is formed by heating to a certain degree and spraying a source gas made of tri-polopooxyaluminum + N2. The thickness of the protective film 6 is preferably 0.05 to 2 μm, more preferably 0.1 to 1 μm, and most preferably 0.2 to 0.5 μm. Except for the formation of the protective film 6, it is the same as the first manufacturing method.
[0028]
In order to obtain the preferable thickness range of the protective film 6, the thickness of the protective film 6 is changed in the range of 0 to 2.5 μm, the defect occurrence rate (%) of the protective film 6 and the IR (insulation after solder reflow) Resistance) change rate (%), connection failure rate (%) to external circuit.
This will be described in detail below.
[0029]
The occurrence of a defect in the protective film 6 is determined by whether or not the plating solution enters the defective part of the protective film 6 between the first and second Ag conductor layers 14 and 15 and reaches the ceramic body 1. did. Therefore, the protective film defect occurrence rate can also be called the plating elongation occurrence rate. When the protective film defect occurrence rate was measured by changing the thickness of the protective film 6, the results shown in the following Table 1 were obtained.
[0030]

[0031]
When the protective film defect occurrence rate in the case where the resin layer 7 was not provided was measured by changing the thickness of the protective film 6, the results shown in the following Table 2 were obtained.
[0032]

[0033]
Change rate (%) of IR (insulation resistance) between the first and second external electrodes 4 and 5 when a laminated varistor having both the protective film 6 and the resin layer 7 is fixed to the circuit board by solder reflow. When the thickness of the protective film 6 was measured, the results shown in Table 3 below were obtained. The change rate of IR indicates the ratio of IR before reflow and IR after reflow.
[0034]

[0035]
Protection of IR change rate (%) between the first and second external electrodes 4 and 5 when a laminated varistor having only the protective film 6 without the resin layer 7 is fixed to the circuit board by solder reflow When measurement was performed while changing the thickness of the film 6, the results shown in Table 4 below were obtained.
[0036]

[0037]
When the contact failure rate (%) of the connection of the multilayer varistor having the protective film 6 and the resin layer 7 to the circuit board by solder reflow was measured while changing the thickness of the protective film 6, the result of the following Table 5 was obtained. It was.
[0038]

[0039]
When the contact failure rate (%) of the connection by the solder reflow to the circuit board of the laminated varistor provided with only the protective film 6 without providing the resin layer 7 was measured while changing the thickness of the protective film 6, the following Table 6 Results were obtained.
[0040]

[0041]
From Table 1 to Table 6, it can be seen that the thickness of the protective film 6 is preferably 0.05 to 2 μm, more preferably 0.1 to 1 μm. In Tables 1 to 6, the case where the protective film 6 is formed by RF sputtering is shown. However, when the protective film 6 is formed by CVD, the same results as in Tables 1 to 6 are obtained. It was.
[0042]
This embodiment has the following effects.
(1) The protective film 6 made of AlxOy is provided not only in the portion where the external electrodes 4 and 5 of the ceramic body 1 are not formed, but also under the external electrodes 4 and 5.
Therefore, the protection at the boundary between the part where the external electrodes 4 and 5 are formed and the part where the external electrodes 4 and 5 are not formed is satisfactorily achieved. That is, the ceramic body 1 of the solder flux at the time of forming the first and second plated layers 16, 17, 18, 19 into the ceramic body 1 and mounting the varistor on the circuit board. It is possible to prevent the ceramic element body 1 from deteriorating, such as the IR characteristics.
(2) The electrical connection between the internal electrodes 2 and 3 and the external electrodes 4 and 5 is achieved by the protrusion of the internal electrodes 2 and 3 when the Ag conductor layers 14 and 15 are baked. Can be easily achieved.
(3) Since the silicon resin layer 7 is formed on the AlxOy protective film 6 and the voids in the protective film 6 are filled with the resin, the protective function can be greatly improved.
(4) Since the protective film 6 is made by the RF sputtering method or the CVD method, the target protective film 6 can be made relatively easily.
[0043]
[Modification]
The present invention is not limited to the above-described embodiment, and for example, the following modifications are possible.
(1) The material of the internal electrodes 2 and 3 may be different as long as it can obtain the same action as Pd. The internal electrodes 2 and 3 may contain Pd as a main component and another metal as a subcomponent.
(2) The protective film 6 may be a substance other than AlxOy as long as it can satisfy the requirements of the present invention.
(3) The conductor layers 14 and 15 of the external electrodes 4 and 5 may be Ag-Pd paste or the like other than Ag.
(4) The composite structure of the AlxOy protective film 6 and the silicone resin layer 7 can also be applied as a protective layer of a ceramic element having a structure in which the protective film 6 is not provided under the external electrodes 4 and 5.
(5) The present invention can also be applied to ceramic elements such as ceramic multilayer capacitors and ceramic multilayer thermistors other than ZnO varistors.
(6) The resin layer 7 can be a polymer resin having a similar function other than silicon.
[Brief description of the drawings]
FIG. 1 is a plan view showing a ZnO multilayer varistor according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
FIG. 3 is a cross-sectional view showing a ceramic body in which a protective film is formed.
FIG. 4 is a cross-sectional view showing an Ag conductor layer formed thereon.
FIG. 5 is a cross-sectional view showing a silicon resin layer 7 formed thereon.
6 is a diagram illustrating a part of the protective film 6 and the silicone resin layer 7 in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ceramic body 2, 3 Internal electrode 4, 5 External electrode 6 Protective film 7 Silicon resin layer 8, 9 Main surface 10, 11, 12, 13 Side surface 14, 15 Ag conductor layer 16, 17 1st plating layer 18, 19 Second plating layer

Claims (5)

An internal electrode formed of Pd or Pd-Ag embedded in the ceramic body and having a property of volume expansion by heating so as to have a ceramic body and an end face exposed at a part of the outer peripheral surface of the ceramic body Preparing a ceramic element chip comprising:
A protective film made of an oxide of aluminum that covers the entire outer peripheral surface of the ceramic body and has a thickness of 0.05 to 2 μm and that can be expressed by AlxOy, where x and y are arbitrary numerical values. And a process of
Applying an external electrode paste so as to cover a part of the outer peripheral surface of the ceramic body through the protective film;
The external electrode pair - to form a result external electrode baking at a temperature in the range of strike the 500 to 800 ° C. the internal electrodes at the same time by volume expansion defeating portion of the protective film by the internal electrode, the internal A method of manufacturing a ceramic element, comprising: electrically connecting an electrode and the external electrode. 2. The method of manufacturing a ceramic element according to claim 1 , further comprising a step of forming a metal layer on the surface of the external electrode by a plating method. And a step of forming a silicone resin layer so as to cover a portion of the protective film not covered by the external electrode;
Method for manufacturing a ceramic element according to claim 1, characterized in that it comprises a step of forming a metal layer on a surface of the external electrode by plating. 2. The method of manufacturing a ceramic element according to claim 1, wherein the protective film is formed by a high frequency sputtering method. 2. The method of manufacturing a ceramic element according to claim 1, wherein the protective film is formed by a chemical vapor deposition method.

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